Recently, over the top video (OTT-V) is a mainstream of streaming services on the Internet. Moving Picture Experts Group phase-Dynamic Adaptive Streaming over HTTP (MPEG-DASH) starts becoming popular as base technology thereof (for example, refer to Non-Patent Document 1).
In MPEG-DASH, a server prepares a group of moving image data of different bit rates for one moving image content, and a client requests a group of moving image data of an optimum bit rate according to a situation of a network bandwidth, so that adaptive streaming distribution is realized.
Also, in current MPEG-DASH, an encoding system capable of predicting a bit rate in advance is assumed as an encoding system of the moving image content. Specifically, as the encoding system of an audio stream, an irreversible compression system and the like of encoding an audio digital signal analog/digital (A/D) converted by a pulse code modulation (PCM) system such that underflow or overflow does not occur with a fixed size buffer is assumed. Therefore, on the basis of a predicted bit rate, scaling is performed on the server which distributes the moving image content.
Also, in recent years, high-resolution audio of higher audio quality than au audio source of a compact disc (CD) attracts attention. As the A/D conversion system of the high resolution audio, there is a direct stream digital (DSD) system and the like. The DSD system is a system adopted as a recording and reproducing system of a super audio CD (SA-CD), and is a system on the basis of one-bit digital sigma modulation. Specifically, in the DSD system, information of the audio analog signal is expressed with density of change points of “1” and “0” using the time axis. Therefore, it is possible to realize high-resolution recording/reproduction independent of the number of bits.
However, in the DSD system, a pattern of “1” and “0” of the audio digital signal change according to a waveform of the audio analog signal. Therefore, a bit generation amount of the audio digital signal after encoding varies depending on the waveform of the audio analog signal in the lossless DSD system and the like in which lossless compression encoding is performed on the audio digital signal A/D converted by the DSD system on the basis of the pattern of “1” and “0”. Therefore, it is difficult to predict the bit rate in advance.